Improvement in steam-boiler furnaces



A To all whom it may concern:

rjrn i PATENT raton.

BEN JAMES HOBSON, 0F HUTCHINSON, KANSAS, ASSIGNCR TO HIMSELF AND WILLIAM H. RICHARDSON, OF CINCINNATI, OHIO.

iMPRovEMENTiN STEAM-Boden FURNACES.

Specification formingpart of Letters Patent No. 1S 1,440, dated August 22, 1876; application filed February'28, 1874.

Be it known that I, BEN JAMEs HoBsoN,

` of Hutchinsom'lteno county, vStateof Kansas,

have invented certain new and useful Improvements in Steam-Boilers, of which the following is a specification:

My invention has for its objects the form and direction of the tubes ofthe boiler that will best secure free circulation, and such discharge therefromv as shall facilitate a separation ofthe steam ,the distribution of the tubes in such anianncr as to offer least obstruction of the gases 5 the most favorable inclination or curvature of the tubes for the rapid absorption of heat; such arrangement of different diameters of tubes as shall cause uniform generation of steam; the dispensingwith grate'- bars where desirable, and the perfect combustion of the gases in the lire-chamber by the utilization of heat generally wasted.

'the tubes practicable, and provide for amore favorable disposition thereof as concerns the number it will be possible to so group ,second, in such an arrangement of the tubes in groups as to conform to the natural contiguration of dame in a tube, the tubes being made ot' different sizes and lengths, in such a manner that the largest and longest are exposed to the hottest part of the flame, and the smallest and shortest located Where the heat is less intense, for' the purpose of preserving a uniform velocity of circulation and a uniform discharge of steam from the tubes in proportion to size; fourth, in the combinar tion and arrangement of the steam-boiler, a draft-blower or forced-air pipes, and an airheater for this draft, for utilizing the waste heat, inducing perfect combustion in the rechamber, and preventing the formation of smoke, the air being introduced into the combustion-chamber at a point or points above the grate and bed of fuel.

Figure 1 is a vertical section of a steamboiler and apparatus containing the greater part ot' my invention. Fig. 2 is aview in section, showing the device by which I succeed in dispensing with grate-bars. Fig. 3 is a cross-section ofthe boiler immediately above the annular air-chamber, and Figetis a moditication in the construction of the heater.

A and B represent, respectively, the inner and outer shells of the boiler. The tubes C are attached at their lower ends tothe shell A, and at their upper-ends to the conical crown-sheet D. l The crown-sheet E, owing to the necessary contracted character of the drawing, is much nearer the sheet D than is ldesirablein practice. In practice, more steam room than is shown in the drawing is requisite.

.at right angles thereto, the presence of the conical sheet D necessitating thebending of the 'upper ends.

By the provision and arrangement of the conical sheet and vbent tubes,l therefore, the right-angle joint is not only effected, but tbe tubes are in such a form as that 'expansion and contraction will not strain the joint of either end.

The curvature of the upper ends, furthermore, so inclines the discharge of water therefrom (in the generation and the liberationof steam) with relation to the natural direction of the escaping steam that a separation of the steam from the water in these discharges is effected at a pointnear the crown-sheet D, and the Water is prevented from projecting into the steam-space,

The tubes are so grouped, as shown in Fig. 1, that the inner row C, at the bottom, give Wide openings between them for the flame to enter, which openings are reduced in width form to the natural configurati-on `of flame, and being curved `upward and inward, soas to contract in lateral extent, also in conformity to the natural form assumed by iiame in a tube or chamber. It is a well-known fact that fflame in all `cases naturally'assumes a tapering pointed form, star-like in cross-section nea-r the apex, as seen in the flame of a burn-j ing candle, and that it will not follow the shape of a cylindrical tube for but a short distance; and I have therefore designed that the spaces between the tubes in my boiler shall conform to this natural formation ofthe flame, rather than be at variance therewith, `and `by this natural concentration combustion issupported and completed.

The tubes C U' C G are of dii'erent sizes and `ot' different lengths; and in order thatthe water may pass through theouter tubes Aas rapidly, and liberate asmuch steam in propor- 1 tion to area, as the inner ones, I arrange them so that the inner ones are the longestand largest, and from that to the outer onesthe length is decreased and the diameter corre` spondingly decreased. i

In some cases I design to dispense with the grate-bars usuallyr employed, and substitute therefor a solid bottom, E, and feed `the fire i with the necessary gases to support the comfbustion by the jets F, which are necessarily` inclined toward the bottom. These jets may be steam surrounded by annular jets of air 5 or jets of air alone may be used. I prefer,

i however, that these jets, whether used with a solid irebed, E, or with grate-bars, as shown in Fig. 1, shall be steam surrounded or united with jets F of air, so highly heated as that it w shall superheat the steam, and that these jets shall concentrate in a common focus, where the heat, in consequence, will Vbe so intense that the gases arising from the coal will be fully consumed and the formation of smoke pre- Vented, the component parts of the steam and air being in the process separated andutilized.

It will be seen by reference to the drawings that my furnace depends for its supply of `air entirely upon that communicated through pipe G, which supplies a forced currentot` air from a blower, or'other apparatus adapted to estab-4 lish and support a current of air. VThis current of air passes through a heater, H, of`

such construction that the air will pas'sin an opposite direction to the products of lcombustion, which operate it substantially as shown inthe heater for which Letters Batent were granted to myself `and William H. Richardson,-0ctober 3, `1871, reissued 1May 28, 1872, so that itstemperature is gradually increased, and it leaves the heater at apoirlt where it is hottest. The products of combustion which operate this heater are conveyed from the furnace `I by pipe J ,.and,after ,passing through thegheater, `escapeatpipe K,the heat so conveyed (which is generally wasted) being utilized in the heating of the air, which is forced 4in by jets Fito support and complete combus- In order` to maiu-` tion and prevent` smoke. tain below the grate at least as high a press- .ure as :isipossible above the re,aduct, L, is provided, which conducts air under pressure from the circular duct M, which feeds jets F.

In Fig. 4 it is seen, as a modification, that in place of arranging for the air to pass around thetubesof the heater, and the products of combustion i through theinterior thereof, this maybe reversed, theair `being then made to pass interiorly,`and the gases exteriorly. As in this furnace the products of combustion are under. .pressurathe door ofthe `furnace shouldnot be opened unnecessarily, and, when open, the escaping gases may be made to ascend ailume orvertical due lover the door, vwhich may be attached to the front of the forced air, from a `blower or other apparatus,l

to the combustion-chamber@ the boiler aboye the grate or hed of fuel, air-heater H, fuelfurnace I, and pipe J, conveying theproducts o1' combustion through the heater H, the parts beingcombined and operating substantially in `the manner and for the purpose specified.

In: testimeuy 0f which invention Ihereunto set my hand,

` EEN JAMES HOBSON. Witnesses:

B" M: HUNTER, J- L WRTMANNf 

